// Scintilla source code edit control
/** @file LexVB.cxx
** Lexer for Visual Basic and VBScript.
**/
// Copyright 1998-2005 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stdarg.h>
#include <assert.h>
#include <ctype.h>

#include "../include/ILexer.h"
#include "../include/Scintilla.h"
#include "../include/SciLexer.h"

#include "../lexlib/WordList.h"
#include "../lexlib/LexAccessor.h"
#include "../lexlib/Accessor.h"
#include "../lexlib/StyleContext.h"
#include "../lexlib/CharacterSet.h"
#include "../lexlib/LexerModule.h"

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

// Internal state, highlighted as number
#define SCE_B_FILENUMBER SCE_B_DEFAULT+100


static bool IsVBComment(Accessor &styler, int pos, int len) {
	return len > 0 && styler[pos] == '\'';
}

static inline bool IsTypeCharacter(int ch) {
	return ch == '%' || ch == '&' || ch == '@' || ch == '!' || ch == '#' || ch == '$';
}

// Extended to accept accented characters
static inline bool IsAWordChar(int ch) {
	return ch >= 0x80 ||
		(isalnum(ch) || ch == '.' || ch == '_');
}

static inline bool IsAWordStart(int ch) {
	return ch >= 0x80 ||
		(isalpha(ch) || ch == '_');
}

static inline bool IsANumberChar(int ch) {
	// Not exactly following number definition (several dots are seen as OK, etc.)
	// but probably enough in most cases.
	return (ch < 0x80) &&
		(isdigit(ch) || toupper(ch) == 'E' ||
		ch == '.' || ch == '-' || ch == '+');
}

static void ColouriseVBDoc(unsigned int startPos, int length, int initStyle,
	WordList *keywordlists[], Accessor &styler, bool vbScriptSyntax) {

		WordList &keywords = *keywordlists[0];
		WordList &keywords2 = *keywordlists[1];
		WordList &keywords3 = *keywordlists[2];
		WordList &keywords4 = *keywordlists[3];

		styler.StartAt(startPos);

		int visibleChars = 0;
		int fileNbDigits = 0;

		// Do not leak onto next line
		if (initStyle == SCE_B_STRINGEOL || initStyle == SCE_B_COMMENT || initStyle == SCE_B_PREPROCESSOR) {
			initStyle = SCE_B_DEFAULT;
		}

		StyleContext sc(startPos, length, initStyle, styler);

		for (; sc.More(); sc.Forward()) {

			if (sc.state == SCE_B_OPERATOR) {
				sc.SetState(SCE_B_DEFAULT);
			} else if (sc.state == SCE_B_IDENTIFIER) {
				if (!IsAWordChar(sc.ch)) {
					// In Basic (except VBScript), a variable name or a function name
					// can end with a special character indicating the type of the value
					// held or returned.
					bool skipType = false;
					if (!vbScriptSyntax && IsTypeCharacter(sc.ch)) {
						sc.Forward();	// Skip it
						skipType = true;
					}
					if (sc.ch == ']') {
						sc.Forward();
					}
					char s[100];
					sc.GetCurrentLowered(s, sizeof(s));
					if (skipType) {
						s[strlen(s) - 1] = '\0';
					}
					if (strcmp(s, "rem") == 0) {
						sc.ChangeState(SCE_B_COMMENT);
					} else {
						if (keywords.InList(s)) {
							sc.ChangeState(SCE_B_KEYWORD);
						} else if (keywords2.InList(s)) {
							sc.ChangeState(SCE_B_KEYWORD2);
						} else if (keywords3.InList(s)) {
							sc.ChangeState(SCE_B_KEYWORD3);
						} else if (keywords4.InList(s)) {
							sc.ChangeState(SCE_B_KEYWORD4);
						}	// Else, it is really an identifier...
						sc.SetState(SCE_B_DEFAULT);
					}
				}
			} else if (sc.state == SCE_B_NUMBER) {
				// We stop the number definition on non-numerical non-dot non-eE non-sign char
				// Also accepts A-F for hex. numbers
				if (!IsANumberChar(sc.ch) && !(tolower(sc.ch) >= 'a' && tolower(sc.ch) <= 'f')) {
					sc.SetState(SCE_B_DEFAULT);
				}
			} else if (sc.state == SCE_B_STRING) {
				// VB doubles quotes to preserve them, so just end this string
				// state now as a following quote will start again
				if (sc.ch == '\"') {
					if (sc.chNext == '\"') {
						sc.Forward();
					} else {
						if (tolower(sc.chNext) == 'c') {
							sc.Forward();
						}
						sc.ForwardSetState(SCE_B_DEFAULT);
					}
				} else if (sc.atLineEnd) {
					visibleChars = 0;
					sc.ChangeState(SCE_B_STRINGEOL);
					sc.ForwardSetState(SCE_B_DEFAULT);
				}
			} else if (sc.state == SCE_B_COMMENT) {
				if (sc.atLineEnd) {
					visibleChars = 0;
					sc.ForwardSetState(SCE_B_DEFAULT);
				}
			} else if (sc.state == SCE_B_PREPROCESSOR) {
				if (sc.atLineEnd) {
					visibleChars = 0;
					sc.ForwardSetState(SCE_B_DEFAULT);
				}
			} else if (sc.state == SCE_B_FILENUMBER) {
				if (IsADigit(sc.ch)) {
					fileNbDigits++;
					if (fileNbDigits > 3) {
						sc.ChangeState(SCE_B_DATE);
					}
				} else if (sc.ch == '\r' || sc.ch == '\n' || sc.ch == ',') {
					// Regular uses: Close #1; Put #1, ...; Get #1, ... etc.
					// Too bad if date is format #27, Oct, 2003# or something like that...
					// Use regular number state
					sc.ChangeState(SCE_B_NUMBER);
					sc.SetState(SCE_B_DEFAULT);
				} else if (sc.ch == '#') {
					sc.ChangeState(SCE_B_DATE);
					sc.ForwardSetState(SCE_B_DEFAULT);
				} else {
					sc.ChangeState(SCE_B_DATE);
				}
				if (sc.state != SCE_B_FILENUMBER) {
					fileNbDigits = 0;
				}
			} else if (sc.state == SCE_B_DATE) {
				if (sc.atLineEnd) {
					visibleChars = 0;
					sc.ChangeState(SCE_B_STRINGEOL);
					sc.ForwardSetState(SCE_B_DEFAULT);
				} else if (sc.ch == '#') {
					sc.ForwardSetState(SCE_B_DEFAULT);
				}
			}

			if (sc.state == SCE_B_DEFAULT) {
				if (sc.ch == '\'') {
					sc.SetState(SCE_B_COMMENT);
				} else if (sc.ch == '\"') {
					sc.SetState(SCE_B_STRING);
				} else if (sc.ch == '#' && visibleChars == 0) {
					// Preprocessor commands are alone on their line
					sc.SetState(SCE_B_PREPROCESSOR);
				} else if (sc.ch == '#') {
					// It can be a date literal, ending with #, or a file number, from 1 to 511
					// The date literal depends on the locale, so anything can go between #'s.
					// Can be #January 1, 1993# or #1 Jan 93# or #05/11/2003#, etc.
					// So we set the FILENUMBER state, and switch to DATE if it isn't a file number
					sc.SetState(SCE_B_FILENUMBER);
				} else if (sc.ch == '&' && tolower(sc.chNext) == 'h') {
					// Hexadecimal number
					sc.SetState(SCE_B_NUMBER);
					sc.Forward();
				} else if (sc.ch == '&' && tolower(sc.chNext) == 'o') {
					// Octal number
					sc.SetState(SCE_B_NUMBER);
					sc.Forward();
				} else if (IsADigit(sc.ch) || (sc.ch == '.' && IsADigit(sc.chNext))) {
					sc.SetState(SCE_B_NUMBER);
				} else if (IsAWordStart(sc.ch) || (sc.ch == '[')) {
					sc.SetState(SCE_B_IDENTIFIER);
				} else if (isoperator(static_cast<char>(sc.ch)) || (sc.ch == '\\')) {	// Integer division
					sc.SetState(SCE_B_OPERATOR);
				}
			}

			if (sc.atLineEnd) {
				visibleChars = 0;
			}
			if (!IsASpace(sc.ch)) {
				visibleChars++;
			}
		}

		if (sc.state == SCE_B_IDENTIFIER && !IsAWordChar(sc.ch)) {
			// In Basic (except VBScript), a variable name or a function name
			// can end with a special character indicating the type of the value
			// held or returned.
			bool skipType = false;
			if (!vbScriptSyntax && IsTypeCharacter(sc.ch)) {
				sc.Forward();	// Skip it
				skipType = true;
			}
			if (sc.ch == ']') {
				sc.Forward();
			}
			char s[100];
			sc.GetCurrentLowered(s, sizeof(s));
			if (skipType) {
				s[strlen(s) - 1] = '\0';
			}
			if (strcmp(s, "rem") == 0) {
				sc.ChangeState(SCE_B_COMMENT);
			} else {
				if (keywords.InList(s)) {
					sc.ChangeState(SCE_B_KEYWORD);
				} else if (keywords2.InList(s)) {
					sc.ChangeState(SCE_B_KEYWORD2);
				} else if (keywords3.InList(s)) {
					sc.ChangeState(SCE_B_KEYWORD3);
				} else if (keywords4.InList(s)) {
					sc.ChangeState(SCE_B_KEYWORD4);
				}	// Else, it is really an identifier...
				sc.SetState(SCE_B_DEFAULT);
			}
		}

		sc.Complete();
}

static void FoldVBDoc(unsigned int startPos, int length, int,
	WordList *[], Accessor &styler) {
		int endPos = startPos + length;

		// Backtrack to previous line in case need to fix its fold status
		int lineCurrent = styler.GetLine(startPos);
		if (startPos > 0) {
			if (lineCurrent > 0) {
				lineCurrent--;
				startPos = styler.LineStart(lineCurrent);
			}
		}
		int spaceFlags = 0;
		int indentCurrent = styler.IndentAmount(lineCurrent, &spaceFlags, IsVBComment);
		char chNext = styler[startPos];
		for (int i = startPos; i < endPos; i++) {
			char ch = chNext;
			chNext = styler.SafeGetCharAt(i + 1);

			if ((ch == '\r' && chNext != '\n') || (ch == '\n') || (i == endPos)) {
				int lev = indentCurrent;
				int indentNext = styler.IndentAmount(lineCurrent + 1, &spaceFlags, IsVBComment);
				if (!(indentCurrent & SC_FOLDLEVELWHITEFLAG)) {
					// Only non whitespace lines can be headers
					if ((indentCurrent & SC_FOLDLEVELNUMBERMASK) < (indentNext & SC_FOLDLEVELNUMBERMASK)) {
						lev |= SC_FOLDLEVELHEADERFLAG;
					} else if (indentNext & SC_FOLDLEVELWHITEFLAG) {
						// Line after is blank so check the next - maybe should continue further?
						int spaceFlags2 = 0;
						int indentNext2 = styler.IndentAmount(lineCurrent + 2, &spaceFlags2, IsVBComment);
						if ((indentCurrent & SC_FOLDLEVELNUMBERMASK) < (indentNext2 & SC_FOLDLEVELNUMBERMASK)) {
							lev |= SC_FOLDLEVELHEADERFLAG;
						}
					}
				}
				indentCurrent = indentNext;
				styler.SetLevel(lineCurrent, lev);
				lineCurrent++;
			}
		}
}

static void ColouriseVBNetDoc(unsigned int startPos, int length, int initStyle,
	WordList *keywordlists[], Accessor &styler) {
		ColouriseVBDoc(startPos, length, initStyle, keywordlists, styler, false);
}

static void ColouriseVBScriptDoc(unsigned int startPos, int length, int initStyle,
	WordList *keywordlists[], Accessor &styler) {
		ColouriseVBDoc(startPos, length, initStyle, keywordlists, styler, true);
}

static const char * const vbWordListDesc[] = {
	"Keywords",
	"user1",
	"user2",
	"user3",
	0
};

LexerModule lmVB(SCLEX_VB, ColouriseVBNetDoc, "vb", FoldVBDoc, vbWordListDesc);
LexerModule lmVBScript(SCLEX_VBSCRIPT, ColouriseVBScriptDoc, "vbscript", FoldVBDoc, vbWordListDesc);

